Rumour: “Laser hair removal causes cancer” — What does the science say?

Short answer: there is no scientific evidence that laser hair removal causes cancer. Unlike X-rays, the lasers used for hair removal use non-ionising light, which does not have enough energy to damage DNA directly. The real risks of laser hair removal are burns, changes in skin colour and damage to unprotected eyes. These risks can be reduced with a suitable device, the right settings and an experienced practitioner; however, they cannot be eliminated.

Where does the rumour come from?

In everyday language, the word radiation is used to describe very different types of energy at the same time. When the high-energy rays from X-rays and some nuclear sources, and daylight, radio waves and laser light are all called by the same word, it is easy to think they all carry the same risk. Yet their effects on the body are very different from one another.

The difference between ionising and non-ionising radiation

In science, radiation is divided into two groups according to its energy. Ionising radiation (for example X-rays and gamma rays) has enough energy to knock electrons out of atoms and can cause direct damage to DNA. This is the type of radiation associated with cancer risk.

The lasers and intense pulsed light (IPL) devices used for hair removal, on the other hand, work in the visible light and near-infrared range. This light is non-ionising. It acts through heat: the light is absorbed by melanin, the dark pigment in the hair root, is turned into heat and damages the hair root.

Ultraviolet light has a special place between these two groups, and its link with skin cancers is well known. Hair removal lasers do not use ultraviolet light.

What does the research say?

Laser hair removal has been widely used for many years. Reviews that have looked at the side effects of this method have not reported any findings of skin cancer developing as a result of laser hair removal. The depth at which the light acts is also limited to a few millimetres of the skin; it does not reach the internal organs.

In science, it is difficult to prove that something never happens, and very long-term follow-up data are limited. However, current knowledge and the physical properties of the light do not support the concern that laser hair removal causes cancer.

The risks that really need attention

Even though the cancer concern is unfounded, laser hair removal is a medical procedure with risks. The most common and most important risks are:

• Burns and blisters: can occur if the device setting is not suitable for the skin type or if the skin has recently been tanned.
• Colour changes: darkening or lightening of the skin may occur; the risk is higher in dark skin and skin that has been in the sun. It is usually temporary, but may last a long time.
• Scarring: rarely, especially after severe burns.
• Eye damage: laser light can seriously harm an unprotected eye. During treatment, both the person being treated and the practitioner must wear suitable protective eyewear; treatment around the eyes requires special care.
• Increased hair growth: in some people, hair growth may unexpectedly increase near the treated area.

Most of these risks can be reduced through an examination, correct identification of the skin type and choice of a suitable device and settings. Sun protection before and after treatment is also important. For detailed information, see our article “Laser Hair Removal”.

Why do moles and spots need special attention?

Because moles also contain melanin, they absorb laser light. Applying laser over a mole can change its appearance. This can make it harder for a physician to assess that mole in the future and may cause a possible sign of skin cancer to be missed.

For this reason, laser should not be applied over moles without an assessment. During treatment, moles are usually protected and skipped. If you have a mole that has changed in shape, colour or size, bleeds or is new, it is advisable to see a dermatologist before hair removal. More information about spots on the skin can be found in the article “Dark Spots and Melasma”.

Conclusion

The rumour that laser hair removal causes cancer comes from different types of radiation being called by the same word. Hair removal lasers use non-ionising light, and there is no evidence that they cause cancer. Nevertheless, there are real risks such as burns, colour changes and eye damage. For the usual course after treatment, see our article “Aftercare Following Medical Aesthetic Procedures”. The decision should be made together with your physician after an examination.